Preparation And Properties Of Dielectric Composites For Embedded Capacitor Application

In a typical printed circuit board (PCB), accounting for less than 3% of the total price of the components may account for 40% of board space. And the situation is becoming worse. We designed the circuit board to support multifunctionality, higher clock speeds and lower voltages, which requires more power and higher current. With the lower noise budget to lower the voltage, the power distribution system for a significant improvement is needed. All of this is needs to have more passive components in a PCB. The benefits of the passive components embedded into the circuit board not just save the space of the circuit board, but also reduce parasitic inductance. The embedded passive components will be reduced to a short length of wire and allow the device more compact layout, thereby improving electrical performance.This thesis focuses on preparation the dielectric composites for embedded capacitor application. In the third chapter, the weight ratio of epoxy resin and curing agent and curing process of heating curves were determined first by DSC. Then FT-IR, TG has been used to characterize the KH550 modified BaTiO₃ . Research results showed that the hydroxyl generated through the hydrolysis of KH-550 was bond together with Ba-O and Ti-O on the surface BaTiO₃ . So that the surface BaTiO₃ achieved the purpose of surface modification by the hydrophilic group turn into a pro-oil-based groups. And then the modified BaTiO₃ was added into epoxy resin. The results of this study found that the modified BaTiO₃ not only well disperse in epoxy resin, the dielectric properties and the peel strength with copper foil of BaTiO₃ -epoxy composites have also been greatly improved.In chapter four of this thesis studied the loading of BaTiO₃ additive effect on the microstructure, peel strength and dielectric properties of the BaTiO₃ -epoxy resin composite. And use the particle size about 100 nm BaTiO₃ added to the epoxy resin, studied the microstructure, peel strength, thermal stress, the surface resistance, dielectric properties with frequency and temperature of the composite. The results show that, the peel strength, thermal stress, and surface resistance of the BaTiO₃ -epoxy composite can meet application requirements, but the dielectric constant is still relatively low (<35, 1 MHz and the temperature≤100℃).In chapter five of this thesis, a higher dielectric constant composite was studied based on percolation theory. The dielectric properties of Cu@SiO₂ -BaTiO₃ -epoxy composites were researched. The Cu particles coated with SiO₂ insulation layer (Cu@SiO₂ ) was added into BaTiO₃ -epoxy resin composite. The results showed that, the join of Cu@ SiO₂ improved the dielectric constant of composites. And because the surface of Cu particles coated with a layer of SiO oxide layer, the electronic transitions between the copper particles was blocked, making the composite material unlike the typical percolation system that the dielectric loss showes a sudden increase when the fraction of conductor approaching the percolation threshold.